Yamaha YZ250F Opinions

[Kerick]

Im looking at a 04 YZ250F and I was wondering everyones opinions on these. I saw an 07 at a local dealership and loved it but it was out of my price range. Did they make any significant updates from 04-09? Plus and minuses on the 250f. Thanks

[300rman]

Minuses: They like to blow up.......

I imagine there are pretty major updates in the early motors that address reliability issues.

[Kerick]

So the older ones are no good and blow up even if you maintain them?

[300rman]

I would have a 125 over a 250f any day of the week. only way you would see me on a 250F is in pro-racing. the 2 stroke 250's can run the 250F's in amateur racing BTW

[oldskool83]

the older ones will not blow up unless you dont mantain them. they are run harder but they also had steel valves up to 2002 that i know of. swap out the titaium valves for some steal ones that will last, make sure the motors all tight and chain oil alot. check your valves alot and your fine.

will you work on them more then an older 4 stroke or new 2 stroke but it should last.

[300rman]

Ive seen plenty of brand new 250f's over the last few years completely grenade with less than 40 hours on them.

[tecat-z]

All of the high strung 250f's and 450 are time bombs. Valve material doesn't cause the super short rod to break in half at 13,000 rpm, rendering the engine completely useless. Due to the cases being completely trenched out by the swinging remains of the rod. Clean oil only goes so far too. It's all about the short cycle life these engines have. Extremely short rod length puts lots of angle stress on them, causing failure. For casual trail riding they will last awhile. But something that old. I'd be very leery. My 450 has been good, but i ride it very little. 2 stroke is the only way to go if you ride hard and abuse them often.

[seantrx250r]

I would not buy any 4 stroke they are junk.If you want to spend a ton of money on a motor than go for it.Just remember the they are time bombs.Ed is very right but you also need to sell the JUNK because I'm not really wanting to pull a wheelbarrow around with me to pick up the pieces from your time bomb either.So best if luck and I would way heavy on a 2 stroke.

[Jason Hall]

Do they all blow up with Under 40 hour's on them???? Give me a break, the problem Is you (300Rman) only remember the bad explosion's you have seen In the past. I think you should ride a CRF250R, or YZ250F and scream the SHIAT out of It bounce It off the rev limiter, then you would realize how silly It Is to over rev one!!! These engine's don't need to srceam wide open like a 2 stroke!!! They make THE BEST power you could ever ask for. I bet most of the blown up bike's with 40 hours on them where absolutly BEAT by X - 2 stroke rider's for those 40 hour's with no oil change's. And I bet If you asked them they were DROOLING over the torque. If you ride the bike without Abusing the thing, change the oil and keep the air filter clean you will love It. The Yamaha engine's are TOUGH as Hell. I say get an older bike, put a New OEM crank In It. A new cylinder & piston, then you will know what you have. You also had fun building It The crank's, cylinder's, and piston's are not that expensive. To buy a used newer 4 stroke without knowing the history Is taking a big chance I will admitt.

I don't agree with the short rod theory completly. I respect and understand what Ed has said, but Yamaha, Honda, Kawasaki, and Suzuki wouldn't all have rods that are to short. I think most of the problem Is Inexperianced people riding these High strung motor's. They pull like CRAZY FOREVER!!! I think If you held any one of the Yanmaha engine's wide open for Mile's It would rev to the friggin Moon and explode all over the place, It would have to. If you treat the engine like that then you got what you deserved IMO. If you treat it like It should be treated, then It will give you Lot's of riding. If you over rev It, and don't maintain It It won't last. These new motor's turn like 4000-5000 RPM's more than your old 2 stroke's, a guy fresh off a 2 stroke will almost alway's over rev a new 4 stroke, because they NEVER stop pulling!!! They just don't sign off like the old 4 stroke's did.

[oldskool83]

i will agree with jason on this, there is a different riding style on these bike. 2 stroke riders normal ride snapping power full throttle, when i started to ride 4 strokes i had to realize i couldnt ride it like a 2 stroke, i ended up over heating them.

how ever 4 stroke street bike you can ride a 2 stroke dirtbikes....so hopfeully in about 10 years they will pass that technologry down to the single cylinder dirtbikes and quads. but until then i only riding my air cooled 80's designed motors just to be safe!

[300rman]

i have rode a few 450's, the newest being an 06. i am thoroughly unimpressed with the motor. All the grenades in pro racing is standing proof that they are not reliable. granted, they are getting better, but........

as for the 250F, i know someone that has a 07 CRF, and he swore it was lightning.....till i blew his ass away with my bike. then he rode it, and needless to say, he was shocked.

[daniel_250r]

i know someone with a 2005 trx 450, never had any thing done other than oil changes and it still runs strong no noises

[Daniel 250es]

I have an 04 yz450f. I had over 400 hours on it before a top end rebuild and valves were still in spec. I could have put 500 hours on top end.
I do change oil frequently. Raced about 50 b class races on it. That motor is bullet proff and the titanium valves way outlast a honda.Also had a kx 250 and kx125 and yz85 all 2 strokes. the 2 strokes cost more because you rebiuld every year. You can go 4 years of hard riding on a 4 stroke before rebuild.

[300rman]

heh heh.....400 hours on a modern thumper that has been raced? im calling BS.

this guy bought the bike new....15 hours into riding it.....well....

http://www.thumpertalk.com/forum/sho...d.php?t=658838

sadly, there are so many stories of low-hour thumpers blowing up over on TT that i cant read em all.

[brucewilliams]

Yamaha YZ250F no bad word fr it because its born to rule with is power and speed